Crankshaft grinding machine



May 6, 1941 c. G. FLYGARE 2,241,342

CNSHAFT GRINDING MACHINE Filed Nov. 22, 1940` 2 sheets-sheet 1' C'HHL IFL YEHHE May 6, 1941. c. G. FLYGARE 2,241,342

CRANKSHAFT GRINDING MCHIN Filed Nov. 22, 1940 @sheets-snm 2 Patented`May 6, 1941 IUNITED STATES PATENT .o1-FICE CRANKSHAFT GRINDING MACHINECarl G. Flygare, Worcester, Mass., assigner to Norton Company,Worcester, Mass., a. porpora.. tion of Massachusetts ApplicationNovember 252, 1940, serial No. 366,681 7 Claims. (o1. -51-237l Theinvention relates to grinding machines, and more particularly to adouble head crankshailt grinding machine.

A#One object of the invention is to provide a simple and thoroughlypractical, readily controllable crankshaft grinding machine. Anotherobject of the invention is to provide a crankshaftI grind-ing machine inwhich both ends of the shailt are rigidly `clamped in opposed alignedwork chucks. A further .object of the .invention is to provide Va workhead construction in which `at least one of the Work `supporting andclamping chucks is `arrangexl to iloat in an axial direction so as toprevent distortion of the shaft during a grinding operation. yOtherobjects will bein part i obvious .or .in part pointed out hereinafter.

The invention accordingly consists in the features of construction,combinations of elements, and `arrangements of parts, as will beexempliiied in the structure to be hereinafter described, and the scopeof the application of which will be indicated in the following claims.

In the accompanying drawings in which is shown one of various possibleembodiments of the mechanical fea-tures of this invention,

Fig. 1 is a front elevation of a crankshaft grinding machine embodyingthis invention, having parts broken away and shown in section, to moreclearly show the construction;

Fig. 2 is .a fragmentary vertical section, on an enlarged scale, throughthe right-hand work supporting head;

Fig. 3 is a cross sectional view, taken approximately on the line 3--3of Fig. y2;

Fig.. 4 .is across .sectional View., taken approxi-4 mately on the line4-4 of Fig. 2;

Fig. 5 is a fragmentary right-hand end elevation of the head as shown inFig. Z, with the cover plate over the universal joint removed, takenapproximately -on the line 5-5 of Fig. 2; and Fig. 6 is a fragmentarycr'oss sectional view, on an enlarged scale, taken approximately on the.line 6-6 ofliig. 2.

A double head crankshaft grinding machine has been illustrated in thedrawings, comprising a base l which supports a transversely 'movableWheel slide |\I carrying arotatable grinding wheel .I2 on la wheelspindle I3 which is journalled in bearings (not shown) in the wheelslide Il. The Wheel slide Il is arranged to slide transversely von theusual V-way and flat way (not shown) on the base l0. The grinding wheell2 may be rotated by any `suitable source of 'power such as, forexample, an electric motor I mounted .on the upper surface of the wheelslide Il. The motor l5 is provi-ded with a driving pulley yit which isconnected by a driving belt l1 with a pulley (not shown) mounted on theright-hand `.end of the wheel Spindle I2.

A longitudinally traversable work supporting table 20 is arranged toslide longitudinally on a ilat way and V-way (not shown) on .the base I0of the machine in a manner similar to that shown in the prior U. S.patent `to Silven, No. 2,151,666 dated March 21, 1939, to whichreferencemay be had for details of disclosure lnot contained herein. Thework table 20 is provided lwith a rotatable work support which ispreferably of a double head type comprising a pair `of opposed aligned`work heads 2| and .22 which in turn rotatably support work holding potchucks 23 and 24, respectively. The pot chucksr 23 and 24 yare providedwith pivctally mounted clamping jaws 25 and 26 rigidly to secure theopposite `ends ci' la crankshaft in position in the chucks, 23 `and 24,respectively. The pivotally mounted clamping jaws 25 and 26 may beautomatically operated by a power operated mechanism 4such as, forexample, that shown in [the U. S. patent to Silven et al., No.1,837,342, dated December 22, 19311. As illustrated in the drawings,however, a `maninrlly operable clamping mechanism is provided,'ccmprising clamping bolts 21 and 28, respectively, which clamp the jaws25 and 26, respectively, -to hold the opposite ends of a crankshaft tobe f ground rigidly in half bearing supports -(not shown) formed in th-epot chucks 23 and 24, respectively.

The pot chucks 23 and 24 are rotatably supported on heads 2| and 22,respectively, and are arrangedA to `be synchronously rotated by means ofan electric motor 30 mounted within the base of the machine. The motor30 is provided with a driving sprocket 3| which is connected by means ofa link lchain 32 with a sprocket 33 which is slidably keyed to arotatable shaft 34. The shaft '34 is rotatably supported in bearing-swhich are fixed to and depend from the under side of the table 20. Theopposite ends .of the shaft 34 are provided with sprockets 35 and 36,respectively. The sprockets 35 and 36 are .connected by link chains 31and 38 with sprockets 39 and 40 synchronously to rotate the .pot chucks23 and 24, respectively.

In a crankshaft grinding machine, it is desirable to steady the Work ata point opposite the operative face of the grinding wheel i2.Consequently a vertically movable steadyrest 41 is provided. Thesteadyrest 4l has not been illustrated and described in detail in thepresent applicacrankshaft.

tion since this steadyrest is not considered to be a part of the presentinvention. The steadyrest 4| is identical with the prior U. S. patent toH. A. Silven, No. 2,053,878, dated September 8, 1936, to which referencemay be had for details of disclosure not contained herein.

In the grinding of crankshaf'ts or other work pieces in a double headmachineV where the opposite ends of the work piece are rigidly clampedin supporting chucks, it is desirable that at least one `of the worksupporting chucks be mounted so .that it may float axially in eitherdirection so that even though excess pressure may be applied by thesteadyrest 4| or the grinding wheel I2 or the pot chuck supportingbearing surfaces may be slightly out of line, the endwise floatingmovement of the chuck will allow the axis of the shaft to remain in thesame relative position, thus enabling precise grinding of cylindricalportions on the work piece, such as the crankpins on a,-"Asjillustrated` in the drawingsfthe right-hand 'work head 22 isprovided with a Iioating mount forthe potchuck 24 whereby.' it may bemoved vaxially inl either direction to compensate for de- `flectioninthe work piece during the grinding operation. .The pot chuck 24 isrigidly fastened `tofa'flange 45 by means of a plurality of cap screws46. `'The flange 45 is formed integral with Y a-shoulder 50 on thespindle 41 and the left-hand [endV ofthe bearing 43 and also a clearancebe- `tweenn`a :ollar 5| Vwhich is threaded onto the right-hand end .ofthe hollow spindle 41 and the -rightfhand end of the bearing 49, thusproviding suii'icient lost motion so that thelspindle 41 together; withthe pot chuck 24 may float axially in either Ydirection during agrinding operation.

VAn yieldahle-device is provided normally to maintain the spindle 41 ina central position with clearance at Yeither end thereof so that when alwork piece has been clamped in an operative po- V. sition inthechuck24, the -work piece together ,with the chuck 2 4 and the spindle 41may float or move axially in either direction during a grindingoperation. A sleeve 52 surrounds the spindle 41. The sleeve 52 is heldagainst endwise movement relative to the spindle 41 by means of a pairof Vcollars 53 and 54 which are locked in adjusted position on thespindle 41. The sleeve 52 is provided with two pairs of spaceddownwardly downwardly projecting lugs 55 and 56 which straddle Vva pairoi upwardly extending spaced .,'111gs`51and58 which are fixed within theframe oftheheadZZ.` .Y

A pair ofu angle ironl membersv 59 and '60 are .slidably supportedbetween the lugs 51 and 58 in *engagement withthe pairs of lugs 55 and55, if'esp'etivelyrlwhich project downwardly from the 's l'e ei`/e"52 lA compression spring 6| is interposed -'bet`vvfeenfthe angle irons 59and E0 and serves f ynormally to maintain the angle ironsI 59 and 50 ispaced/'from` each other in Yengagement with the lugs55-56 and 51-'-58,respectively. It will be readily apparent from` theioregoingV disclosureKNthat-any axial or .endwise thrust on'the hollow Q spirudlel 41wills'erve through the lugs 55 and 56 tompve either the angle iron 59 orthe angle iron u 50f-towardtheotheigf thus `compressing the .spring 6|Yso that the spindle 41 together with.

the pot chuck 24 supported thereby is free to by the ange 45. The innerends of the studs 12 and 13 are supported in bearings 14 and 15,respectively, which are in turn supported in the gimbal ring 1|, thusforming a universal joint connection .between the drive shaft 65 and the1 ila-nge 45 orgthe chuck end of the hollow spindle The driving gear orsprocket 49 is arranged to transmit a rotary motion to the driving shaft55 and through the universal joint 61 to rotate the sleeve 41 and thepot chuck 24. v-It is desirable that a suitable driving `connection beprovided between the sprocket 40 and the right-hand end of the driveshaft 65 so that lost motionwill be eliminated inthe driving connection,and the connections being so rarranged that the shaft 55 may readilyiioat in an axial direction as governed by thespindle 41. A rotatablesleeve 8i! serves as a support for the driving sprocket 40 and thesleeve 8| formed integrally therewith. The sleeve 89 is slidably keyedby means of a key 82 with a rotatable sleeve 33 which is in turnsupported by an anti-friction bearing 84. T he bearing 84 is iixedlysupported in a frame which is either xedly or rigidly supported onthework supporting table 20. The sprocket 4t] and its integral sleeve 8|are slidably connected by a key 8S with a rotatable sleeve 81 which isin turn journalled in an anti-friction bearing 83. The bearing 58 isfixedly supported in the frame 85.

The sleeve 83 is providedv with 'an integral flange 89 by means' ofwhich the sleeve 85 is clamped in xed relation with the sprocket bymeans of a plurality of screws 95 which pass through elongated slots 9|and are screw threaded into the sprocket 49.

Itis desirable t0 provide means whereby the spindle 41 and pot chuck 24may berotatably adjusted to align the chuck 24 with the chuck 23. Thismay be accomplished by loosening the screws 99 andadjusting a pair ofopposed adjusting screws 92 and 93 which are carried by vupwardlyextending lugs 94 andY 95 formed inte-v gral with theflange 89. The endsof the adjusting screws 92 and 93 are arranged-to cngage opposed facesof a stud 9 3 which is carried by the sprockets 40. It will be readilyapparent from lthe foregoing'disclosure that the. sprocket may beangularly or rotatably adjusted relative to the sleeve 89, after whichitA lmay be readily clamped in adjusted position bytightening oneor'more clamping screws 9 0 '(only one of which has been shown in thedrawings).

A universal joint is provided between the 1'0- tatable sleeve 8|) andthe shaft 65. A universal joint housing |59 is slidably keyed on thesleeve 8| by means of a key Illl.V The universal joint housing serves asa supportior a pair of diametrically opposed studs v|02 and |D3. Theinner ends of the studs |52 and |03 are journalled in bearings A|04`and. |05, respecti vely, which are in turn carried by a gimbal ring|05. The gimbal ring |06 is connected by Ya pair of studs |01 and |08with a sleeve |09 which ismin turn keyed to` the right-hand' end of thedrive shaft 65 in amanner to be hereinafter described. The studs |01 and|08 are fixedly mounted infthe sleeve |08 andi arejournalled inbearings' |:|.0and I, respectively, which are carried by the gimbal ring|06, thus forming a. universal driving. connection between the drivingsprocket 40 and the drive shaft 65.

In` order to provide an` adjustable slidable. connection between theuniversalv joint andthe shaft 65, the sleeve |09.V is a split sleevehaving a plu.- ralityv of slots H2, ||3:,. |l4', |15, H6 and |i|1extending through the end; portion at the righthand end of the sleeve|09. The sleeve |110 is provided with a. pair of tapered keyways |20.and |2| to receive a pair of driving Ykeys |22 and |23, respectively.YThe keys |221 and |23 are shaped to fit Within` taperedv splines |24 and|25 respectively,v formed in the shaftv 65. Adjusting screws |26 and|121 are provided at the ends of the keys |22 and' |23. The adjustingscrews, |26 and. |21 are screw threaded intothe endof the sleeve |08.Adjustment off the keys ini a direction toward the left. will wedge: thekeys |22 and |23r into. a rigidi lockedJ position. securely1 to lock thesleeve |09 i-n adjusted position relative to thet shaft 65. A lockingcollar |330 is screw` threaded onto the right-hand end. of the sleeve||l9k and isv provided with an internal tapered aperture which Vfits atapered mating face on the' .split portion.l of the sleevek |09. Bytightening thejsleeve |30 after the parts have been adjusted topredetermined positions, the sleeve |091together with the keys |22 and|23, respectively,A may be locked inv a .lo

rigid adjusted positionrelative to the shaft 65.

In order that the sleeve 80, together with the sprocket 40 and theuniversal joint housing; |00 together with the parts carriedtherebyinay-fioat in an axial direction with the shaft 65, al yieldableconnection is provided comprising a plurality of springs |32 which. areinterposed between apertures in a pair of spaced collars '|33 and |34which loosely fit within an aperture within the sleeve 81. The collars|33 and |34 together with the springs |,32are held imposition by meansof an end cap |35 which is fixedly mounted to the sleeve 81. The collar|33 is engaged by the right-hand end face ofA the sleeve 8| and thecollar |34 is engaged by a shoulder formed on the universal. jointhousing |00. The integral sleeve formed with the housing is held inposition on the sleeve 80 against the end of the sleeve 8| by means of acollar |36.

It will be readily apparent from the foregoing disclosure that when theshaft 65 floats in a direction toward the left, the shoulder on theuniversal joint housing |00 will move the collar |34 toward the left,thus compressing the springs |32 so that the entire driving mechanismfloats toward the left with thepotgchuck 24, thehollow spindle 41, andthe drive shaft 65. Similarly, if the chuck 24, hollow spindle 41, andshaft B float in a direction toward the right, the sleeve 8| whichengages the collar |33 will compress the springs |32 during the floatingmovement of the parts toward the right; When the end thrust or pressureon the chuck 24 is released, the released compression of the spring |32serves to return the parts to a central position so that 'f they areagain free to float in either direction, depending upon the thrust ofthe work piece upon the chuck 24 during a grinding operation.

It is desirable to provide a floating action for one spindle only and toutilize the other spindle,

namely', the left-hand spindle, supported in. the

work head 2|, for rotating the chuck 23 so that it has; no endwise,floating adjustment. The construction of the left-hand work headV 2| issubstantially the same as the construction illustrated, in Figs. l and 2for the work head 22 except that the springs providing a yieldable floatfor the spindle are removed and end thrust means provided to hold theparts againsty endwise floating movement. Consequently,V illustrationlisy made onlyv of the right-hand head construction.

Itv will be readily apparent from the foregoing disclosure that bylocking,r opposite ends of the work piece to be ground in the pot chucks23 and 24 and maintaining the pot chuck 23 against axial movement, thechuck 24 together with the parts associated therewith may readily floatin an endwise direction, thus preventing undue distortion of the shaftduring the grinding operation. Any deflection of the shaft may bereadily absorbed by the floating movement of the spindle during thegrinding operation, thus facilitating the.v grinding of precisecylindrical crankpins on a crankshaft.

The operationof this mechanism will he readily apparent from theforegoing disclosure. Assuming al1 of the parts to have been previouslyAadjusted,v a crankshaft to be ground is placed in position in the potchucks 23 and 24 and the work clamping jaws 25. and 2B swung into`place, after which the clamping bolts 21 and 28 are tightened to lockthe jaws 24 and 25 rigidly to support opposite. ends of a crankshaftbeing ground. The work rotation is then started and the pot chucks 23and 24 synchronously rotated during the grinding operation. Thesteadyrest 4| is moved vertically into a supporting position oppositethe operative baseof the grinding wheel l2 and the grinding wheel I2 maythen be moved toward the axis of the work piece to grind the same. Thepot chuck 23 together with itssupporting spindle are held against axialmovement, which denitely locates the shaft in a predetermined positionrelative to the head 2| and table 20. The pot chuck 24 is arranged tofioat axially in either direction While being synchronously rotated withthe pot chuck 23 which facilitates the compensation of any deecting. ofthe axis of the crankshaft from its normal path either due to its ownweight or to the pressure of the steadyrest 4| or the grinding pressureof the grinding wheel I2.

It will thus be seen that there has been provided by this inventionapparatus in which the various objects hereinabove set forth togetherwith many thoroughly practical advantages are successfully achieved. Asmany possible embodiments may be made of the above invention and as manychanges might be made in the embodiment above set forth, it is to beunderstood that all matter hereinbefore set forth or shown in theaccompanying drawings is to be interpreted as illustrative and not in alimiting sense.

I claim:

l. In a grinding machine having a transversely movable rotatablegrinding wheel and a longitudinally movable rotatable work supportincluding a pair of spaced aligned work heads, a rotatable hollowspindle supported in each head, bearings in said heads for said spindle,at least one of said spindles being arranged to float axially in eitherdirection, a work supporting pot chuck on each of said spindles, adriving shaft extending through said hollow spindles, a univ universalversal joint driving'ly connecting one end of said shaft with the chuckend of said spindles, and means including driving connections adjacentto the other end of said driving shaft synchronously to rotate said potchucks.

' 2. In a grinding machine having'a transversely movable rotatablegrinding wheel and a longitudinally movable rotatable work supportincluding a pair of spaced aligned work heads, a rotatable hollowspindle supported in each head, bearings in said heads for said spindle,at least one of said spindlebeing arranged to iioat axially in eitherdirection, yieldable means normally to maintain said spindle in acentral position, a

work supporting pot chuck on each of said spindles, a driving shaftextending through said hollow spindles, a universal joint drivinglyconnecting one end of said shaft with the chuck end of said spindles,and means including driving connections adjacent to the other end ofsaid driving shaft synchronously to rotate said pot chucks.

3. In a grinding machine having a transversely movable rotatablegrinding wheel and a longitudinally movable rotatable work supportincluding a work head, a hollow spindle rotatably journalled in saidhead, lawork holding pot chuck on one end of said spindle, an axiallyaligned rotatable hollow sleeve journalled in said head and spaced fromsaid spindle, a driving sprocketV on said Second sleeve, a driving shaftextending through 'central apertures in said hollow spindle and sleeve,universal driving connections between one end of said shaft and thespindle, -a sleeve slidably keyed to the other end of said shaft, and:driving connections between said sleeves,v said parts being arranged tofacilitate an endwise floating movement of the pot chuck and spindle.

4. In a grinding machine having a transversely movable rotatablegrinding wheel and a longitudinally movable rotatable work supportincluding a pair ofv spaced aligned work heads, a rotatable hollowspindle supported in each head, bear- Yings in said heads for saidspindles, atleast one yof said spindles being arranged to fioat in anaxial direction, awork supporting pot chuck on each of said spindles, adriving .shaft extending through said hollow spindles, a universal jointconnected between one end of said shaft and the chuck end of saidspindles, and splined driving connections adjacent to the otherj end ofsaid drive shafts synchronously to rotate 'said pot chucks.

5. In a grinding machine having a transversely@ movable rotatablegrinding wheel and a longitudinally movable rotatable work supportincludv2,241,3fie

ing a pair of-spaced aligned work heads, each of said heads having arotatable work supporting chuck, at leastone of said heads having arotatable hollow spindle which is arranged to float in an axialdirection, bearings for said spindle in said head,l a hollow sleeverotatably journalled in said head in axial alignment with said spindle,a f driving shaft extending through clearance apertures in said spindleand sleeve, a universal joint connecting said shaft with the chuck endof said spindle, means positively to rotate said sleeve, and lasecond'universal joint connecting said sleeve and shaft, said jointbeing slidably adjustable and drivingly connected with said shaft. Y

6. In a grinding machine having a transversely movable rotatablegrinding wheel and a longitudinally movable rotatable work supportincluding a'pair of spaced aligned work heads, each of said heads havinga rotatable work supporting pot chuck, at least one of said heads havinga rotatable hollow spindle which is arranged to float in an axialdirection, bearings for said spindle in said head, a hollow sleeverotatably journalled in said head in axial alignment with said spindle,a driving shaft extending through a clearance aperture in said spindleand sleeve, a universal joint connecting said shaft with the chuck endof said spindle, means positively to rotate said sleeve, a seconduniversal joint connecting said sleeve and shaft, splined drivingconnections between said universal joint and said shaft to facilitatelongitudinal adjustment, and means to lock said splined connection inadjusted position relative to said shaft.

7. In a grinding machine having a transversely movable rotatablegrinding wheel'and a longitudinally movable rotatable work supportincluding a pair of spaced aligned work heads, a rotatable hollowspindle supported in each of Asaid heads, bearings in 'one of said headsfor rotatably supporting the spindle and holdingv it against axialmovement, bearings in the other of said heads for said spindle which arearranged so that the spindle may float axially in either direction,yieldable means normally to maintain said latter spindle in a centralposition, a work supporting pot chuck on each of said spindles, adriving shaft extending through said hollow spindles, a universal jointdrivingly connecting one end of each shaft with the chuck end of eachspindle, and splined driving connections during a grinding operation.

CARL G. FLYGARE.

